This invention relates to exhaust system manufacturing and more particularly to a method of mechanically locking components of exhaust treatment devices.
Many exhaust treatment devices, including mufflers and after-treatment devices, are formed from multiple components which are coupled together. An exhaust treatment device often includes a pipe component which passes through another component and is coupled thereto. In common configurations of vehicle mufflers, for example, a louvered pipe passes through apertures formed in baffle plates enclosed in a muffler shell. The louvered pipe is coupled to the baffle plate during assembly and manufacture of the muffler. Exhaust treatment devices are disclosed in Herold, U.S. Pat. No. 5,801,344, issued Sep. 1, 1998, and Howe et al., U.S. Pat. No. 4,961,314, issued Oct. 9, 1990, which are hereby incorporated by reference herein.
Another exhaust system is disclosed in pending U.S. application Ser. No. 09/627,500, entitled xe2x80x9cMethod of Coupling Exhaust Components To One Anotherxe2x80x9d, which is also incorporated by reference herein. The exhaust system includes a method of assembling exhaust components that includes, among other things, the steps of providing an exhaust component with an aperture and providing a mating exhaust component having an end sized to be received through the aperture. A stop is formed on the mating exhaust component which will serve as a first half of a coupling mechanism prior to insertion of the mating exhaust component in the aperture of the exhaust component. The end of the mating exhaust component is urged through the aperture in the exhaust component until the stop engages the exhaust component and is simultaneously deformed to form a second half of the coupling mechanism. The components of such an exhaust device may be coupled by forming a stop on the exterior of a component to be inserted through an aperture in second component prior to insertion of the first component. In certain embodiments, the first component is a pipe and the second component is a baffle plate. The pipe is inserted through the aperture formed in the baffle plate until the stop contacts a first wall of the baffle plate. After the stop engages the first wall of the baffle plate, the end of the pipe extends only slightly beyond a second wall of the baffle plate. The end of the pipe is flared until the flared end contacts the second wall of the baffle plate, thereby mechanically locking the two components.
Although the method of the exhaust system referred to above provides several advantages over existing coupling or locking systems, the method in accordance with the present invention is more efficient and effective than the above method and other heretofore known existing methods. The method of the present invention provides a stronger and more durable bond than existing methods for coupling or locking together exhaust components, and is easier and less expensive to use than existing methods. Additionally, the tooling that can be used to perform the method in accordance with the present invention is more economical and more durable than tooling used in connection with existing methods. Moreover, the method of the present invention can be readily used with exhaust pipes having small diameters, such as those having diameters less than 1xc2xd inches, and still provide a strong and durable bond.
In accordance with these and other objects, the present invention provides a method of assembling exhaust components comprising the steps of: (a) providing an exhaust plate or other exhaust component having a first side, a second side, and an embossment, the embossment defining an aperture and a void contiguous with the aperture; (b) providing an exhaust pipe or other mating exhaust component having an end portion including a leading end, the end portion sized to be received by the void; (c) inserting the end portion of the exhaust pipe into the void; and (d) bending a portion of the embossment over the leading end of the end portion to lock the exhaust plate to the exhaust pipe. Desirably, step (d) includes flaring the embossment and a leading portion of the end portion of the exhaust pipe. The method also may include the step of forming the embossment in the exhaust component prior to step (a). The forming step may include punching the exhaust plate with a tool to form the embossment in the exhaust component.
In a preferred embodiment, step (d) is performed by punching the embossment with a punch to deform the embossment and the leading portion of the end portion of the exhaust pipe. The punch may be aligned with the embossment and with a passage defined by the exhaust pipe and punching the embossment bends a portion of the embossment over the leading end of the end portion and into the passage and desirably also flares outwardly the embossment and the leading portion of the exhaust pipe. The aperture desirably is generally circular and the embossment is disposed substantially about the aperture. The void desirably is generally cylindrical to receive the exhaust pipe.
Accordingly, the method of locking together exhaust components in accordance with a preferred embodiment causes a strong and durable coupling between the components. Moreover, the method is efficient and inexpensive and does not require a mandrel to expand any components; rather, a single punch causes the components to lock together in accordance with a preferred embodiment. Still further, the method can readily be used with pipes having diameters less than 1xc2xdxe2x80x3.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.